using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.ComponentModel.Composition;
using System.ComponentModel.Composition.Hosting;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;
using QWPlatform.SystemLibrary.LogManager;
using QWPlatform.SystemLibrary.Utils;


namespace PMS.Interface
{
    /// <summary>
    /// 创 建 人：王海洋
    /// 创建日期：2018-12-10
    /// 功能描述：接口实例化工厂处理类
    /// </summary>
    public class InterfaceFactory
    {
        //缓存实例，如果在缓存中存在，直接返回
        private static ConcurrentDictionary<int, object> _cacheObject = new ConcurrentDictionary<int, object>();
        //private static Assembly businessAssembly = null;
        private static object locker = new object();


        /// <summary>
        /// 创建一个实例化工厂
        /// </summary>
        /// <typeparam name="T">指定泛型的接口</typeparam>
        /// <returns></returns>
        public static T CreateBusinessInstance<T>() where T : class
        {
            var obj = default(T);
            var t = typeof(T);
            var hashCode = t.GetHashCode();

            if (_cacheObject.ContainsKey(hashCode))
            {//缓存中存在。
                return _cacheObject[hashCode] as T;
            }
            else
            {//重新创建实例 
                obj = CreateInstance<T>();
                if (obj != null && !_cacheObject.ContainsKey(hashCode))
                {//添加到缓存中
                    _cacheObject.TryAdd(hashCode, obj);
                }
                else
                {
                    //throw new NotImplementedException("业务对象创建为空:" + t.FullName);
                    Logger.Instance.Error("业务对象创建为空");
                }
            }//end 

            return obj;
        }

        //创建实例
        private static T CreateInstance<T>() where T : class
        {
            var obj = default(T);
            var t = typeof(T);
            try
            {
                var appPath = Path.Combine(Strings.AppDomainPath, "ZLSoft.PMS.BusinessService.dll");

                if (!File.Exists(appPath))
                {//未找到业务体dll
                    throw new FileNotFoundException("未找到业务实现dll文件", appPath);
                }
                 
                var businessAssembly = Assembly.Load("ZLSoft.PMS.BusinessService");

                var type = businessAssembly.GetTypes().First(p => p.GetInterface(t.Name) != null);
                if (type != null)
                {
                    obj = (T)businessAssembly.CreateInstance(type.FullName);
                }

                return obj;

                //var types = businessAssembly.GetTypes();
                //foreach (var type in types)
                //{
                //    var itype = type.GetInterface(t.Name);
                //    if (itype != null)
                //    {//找到实现的实体类

                //        obj = Activator.CreateInstance(type) as T;

                //        // obj = businessAssembly.CreateInstance(type.FullName) as T;
                //        if (obj != null)
                //        {//已到相应的实例，退出循环 
                //            return obj;
                //        }
                //        else
                //        {
                //            throw new QWPlatform.SystemLibrary.CustomException.DataConvertException("创建的业务实例为空对象", type.FullName, null);
                //        }
                //    }//end if
                //}//end foreach
            }
            catch (Exception ex)
            {
                Logger.Instance.Error("加载业务实现DLL异常", ex);
                throw new NotImplementedException("业务DLL没实现了最新定义的接口，可以尝试将业务层PMS.BusinessService.dll复制到运行的Bin目录下。" + ex.Message);
            } 
        }

        /// <summary>
        /// 将所有实例对象清空
        /// </summary>
        public static void ClearCache()
        {//清空缓存
            _cacheObject.Clear();
        }
    }
}